sun certified java programmer scjp exam

Java Programming Language

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Table of Contents

1. Java Programming LanguageStringsConstructorsInner classFlow ControlDeclarations and Access ControlInterfaces and Abstract ClassesExceptionsInheritanceArraysOperatorsVariables and MethodsWrappers and AutoboxingGarbage CollectionOverriding and OverloadingCollectionsGenericsFormattingI/OThreadsEnumsData TypesStatic and init blocksSerializationVarargs


1. Chapter: Strings

1. Strings Questions


1.1.1. Question: Select the common methods, which are defined for both type String and typeStringBuffer ?

Select the common methods, which are defined for both type String and type StringBuffer ?

Please choose all the answers that apply: toString()length()append(String)trim()equals(Object)


Check the answer of this question online on QuizOver.com:Question: What are common methods between String and StringBuffer?Permalink: http://www.quizover.com/pdf/what-are-common-methods-between-string-and-stringbuffer


1.1.2. Question: Given the following code, what is the expected output?

Given the following code, what is the expected output?

Please choose only one answer: 0 ab345 f00 ab344 ef01 b35 f01 b345 f0


import java.util.regex.Matcher;import java.util.regex.Pattern;public class Tester {public static void main(String[] args) { Pattern p = Pattern.compile("[a-f]\\d+"); Matcher m = p.matcher("ab34ef0"); while(m.find()) {System.out.print(m.start()+" "+m.group()); }}}

Check the answer of this question online on QuizOver.com:Question: How to parse String in java?Permalink: http://www.quizover.com/pdf/how-to-parse-string-in-java


1.1.3. Question: What is the correct answer?

What is the correct answer?

Please choose only one answer: Stringbuffer methodString methodnullcompilation errorRuntime Exception

Author: MrDick LAST NAME

public class Test {public void method(StringBuffer sb) {System.out.println("StringBuffer method");}public void method(String s) {System.out.println("String method");}public static void main(String[] args) {Test test = new Test();test.method(null);}}

Check the answer of this question online on QuizOver.com:Question: java string and stringbufferPermalink: http://www.quizover.com/pdf/java-string-and-stringbuffer

Ammar AhmedHighlight


1.1.4. Question: What is the correct output?

What is the correct output?

Please choose only one answer: javacamp_c2012cjavachamp_champ2012champcompliation error in line10615Runtime exception due line 1


class Test {

public static void main(String[] args) { String jc = "javachamp_champ2012champ"; Pattern p = Pattern.compile(".{4}c+(m)*"); //line 1 Matcher m = p.matcher(jc); while(m.find()) {System.out.print(m.start()); }}}

Check the answer of this question online on QuizOver.com:Question: java regex and patternPermalink: http://www.quizover.com/pdf/java-regex-and-pattern


1.1.5. Question: What is the result of compiling and running the following code?

What is the result of compiling and running the following code?

Please choose only one answer: JavaChamp is here to help youJavaChamp i here to help youNo output is producedCompilation error


public class Tester {public static void main(String[] args) {String stmt = "JavaChamp is here to help you";for (String token : stmt.split("//s")) {System.out.print(token + " ");}}}

Check the answer of this question online on QuizOver.com:Question: how to split String in java?Permalink: http://www.quizover.com/pdf/how-to-split-string-in-java


1.1.6. Question: What is the expected output?

What is the expected output?

Please choose only one answer: truefalse

Author: Yasser Ibrahim

public static void main(String[] args) { boolean stmt1 = "champ" == "champ"; boolean stmt2 = new String("champ") == "champ"; boolean stmt3 = new String("champ") == new String("champ"); System.out.println(stmt1 && stmt2 || stmt3);}

Check the answer of this question online on QuizOver.com:Question: Java objects comparisonPermalink: http://www.quizover.com/pdf/java-objects-comparison




Please choose only one answer: javachampjavachamp javachampNo output is producedCompilation error


public class Tester {public static void main(String[] args) {String s = "";Integer x = 5;StringBuffer sb = "";if (x < 0)s.concat("javachamp");elsesb.append("javachamp"); System.out.print(s + sb);}}

Check the answer of this question online on QuizOver.com:Question: How to use java StringBuffer?Permalink: http://www.quizover.com/pdf/how-to-use-java-stringbuffer


1.1.8. Question: Which of the following methods can be invoked by an object of Pattern class?

Which of the following methods can be invoked by an object of Pattern class?

Please choose all the answers that apply: compilematchesgrouptoString


Check the answer of this question online on QuizOver.com:Question: Methods of java regex Pattern?Permalink: http://www.quizover.com/pdf/methods-of-java-regex-pattern


1.1.9. Question: Which of the statements would evaluate to true?

Which of the statements would evaluate to true?

Please choose all the answers that apply: stmt1stmt2stmt3stmt4stmt5


public class Tester {public static void main(String[] args) {StringBuffer sb = new StringBuffer("javachamp");String s = new String("javachamp");boolean stmt1 = s.equals(sb) ;boolean stmt2 = sb.equals(s) ;boolean stmt3 = sb.toString() == s ;boolean stmt4 = sb.toString().equals(s) ;boolean stmt5 = s.equals(sb.toString()) ;}}

Check the answer of this question online on QuizOver.com:Question: What is the difference between String and StringBuffer?Permalink: http://www.quizover.com/pdf/what-is-the-difference-between-string-and-stringbuffer




Please choose only one answer: RuntimeException is thrown because of the first print statementRuntimeException is thrown because of the second print statementnullnullnullnullnullnullcompilation error


public static void main(String args []) {String stmt = null; System.out.print(null+stmt); System.out.print(stmt+null);}

Check the answer of this question online on QuizOver.com:Question: Concatenating String and nullPermalink: http://www.quizover.com/pdf/concatenating-string-and-null




Please choose only one answer: IntBooleanIntBooleanIntIntIntCompilation error


import java.util.Scanner;public class Tester {public static void main(String[] args) {Scanner sc = new Scanner("javachamp 2009, true 239");while (sc.hasNext()) {if (sc.hasNextBoolean())System.out.print("Boolean");if (sc.hasNextInt())System.out.print("Int");sc.next();}}}

Check the answer of this question online on QuizOver.com:Question: How to use java.util.Scanner?Permalink: http://www.quizover.com/pdf/how-to-use-javautilscanner




Please choose only one answer: javachamp.comjamp.comjampjamp.comjavachampjampjap


public class Tester {public static void main(String[] args) {String str = "java";StringBuffer sb = new StringBuffer("javachamp");sb.insert(9, ".com");str.concat("champ");if (sb.length() < 6 || str.equals("javachamp")) {System.out.print(sb);}sb.delete(2, 7);System.out.print(sb);}}

Check the answer of this question online on QuizOver.com:Question: What are java StringBuffer methods?Permalink: http://www.quizover.com/pdf/what-are-java-stringbuffer-methods






public static void main(String[] args) {StringBuffer buffer1 = new StringBuffer("javachamp");StringBuffer buffer2 = new StringBuffer(buffer1);if (buffer1.equals(buffer2))System.out.println("true");elseSystem.out.println("false");}

Check the answer of this question online on QuizOver.com:Question: Comparing StringBuffer using equals in javaPermalink: http://www.quizover.com/pdf/comparing-stringbuffer-using-equals-in-java




Please choose only one answer: javachampjavachamp javachampNo output is producedCompilation error


public class Tester {public static void main(String[] args) {String s = "";Integer x = 5;StringBuffer sb = new StringBuffer();if (x < 15)s.concat("javachamp");elsesb.append("javachamp"); System.out.print(s + sb);}}

Check the answer of this question online on QuizOver.com:Question: How to use StringBuffer in java?Permalink: http://www.quizover.com/pdf/how-to-use-stringbuffer-in-java


1.1.15. Question: What is the result of compiling and running the following program?

What is the result of compiling and running the following program?

Please choose only one answer: Compilation errorfalsefalsetruetruetruetruetruetruetruefalsetruetrue


public class Tester {public static void main(String[] args) {String a = "javachamp";String b = "javachamp";String c = new String("javachamp");System.out.print(a==b);System.out.print(a==c);System.out.print(b.equals(c));System.out.print(b.equals(a));}}

Check the answer of this question online on QuizOver.com:Question: Comparing Strings for equality in javaPermalink: http://www.quizover.com/pdf/comparing-strings-for-equality-in-java


1.1.16. Question: Choose the correct(s) :

Choose the correct(s) :

Please choose all the answers that apply: Can not be used private abstract at // 0

Can not be used abstract static at // 1OK. Compiles Fine !The IOException can be changed to InterruptedExceptionError at // 3Error at // 4

Author: Diogo Dantas

abstract interface Veloz { void metodo(String x); }public class A { private abstract interface Veloz{ Number metodo(int x); } // 0 abstract static class B{ // 1private abstract static interface Veloz{void metodo(long x) throws Exception;}public void metodo(){class Opa implements Veloz{public void metodo(long x) throws IOException {} // 2}}} public void test(){class Opa2 implements Veloz{public Integer metodo(int x) throws RuntimeException { // 3return (Integer)(int) .5f; //4}}}}


Check the answer of this question online on QuizOver.com:Question: Diogo Dantas /** AFTER COMPILING THIS FILE test.java THAT CONTAINS: **/abstract interface VelozPermalink: http://www.quizover.com/pdf/diogo-dantas-after-compiling-this-file-test-java-that-contains-abstract-interface-veloz


1.1.17. Question: What will be the output upon running this piece of code?

What will be the output upon running this piece of code?

Please choose only one answer: CollectionListcompilation error

Author: Divya Nagaraj

public class Test {public static void hello(Collection x) {System.out.println("Collection");}public static void main(String[] args) {Test t = new Testing();List x = null;t.hello(x);}}class Testing extends Test {public static void hello(List x) {System.out.println("List");}}

Check the answer of this question online on QuizOver.com:Question: divya nagaraj public class Test {public static void hello(Collection x){ System.out.printPermalink: http://www.quizover.com/pdf/divya-nagaraj-public-class-test-public-static-void-hello-collection-x-system-out-print2064456


1.1.18. Question: Which of the statements will evaluate to true?

Which of the statements will evaluate to true?

Please choose only one answer: stmt1stmt2stmt3stmt4


public class Tester {public static void main(String[] args) {StringBuffer sb1 = new StringBuffer("javachamp");StringBuffer sb2 = new StringBuffer("javachamp");boolean stmt1 =sb1.equals(sb2) ;boolean stmt2 = sb1 == sb2;

String s1 = new String("javachamp");String s2 = new String("javachamp");boolean stmt3 = s1.equals(s2);boolean stmt4 = s1 == s2;

}}

Check the answer of this question online on QuizOver.com:Question: Comparing String and StringBuffer in javaPermalink: http://www.quizover.com/pdf/comparing-string-and-stringbuffer-in-java






public static void main(String[] args) { boolean stmt1 = "champ" == "champ"; boolean stmt2 = new String("champ").equals(new String("champ")); boolean stmt3 = "champ".toString()=="champ"; System.out.println(stmt1 && stmt2 && stmt3);}

Check the answer of this question online on QuizOver.com:Question: How to compare java objects?Permalink: http://www.quizover.com/pdf/how-to-compare-java-objects




Please choose only one answer: "AB" will be printed"A" will be printed followed be a NullPointerException thrown"B" will be printedNo output is produced


public static void main(String[] args) {String s1 = null;String s2 = null;

if (s1 == s2)System.out.print("A");if (s1.equals(s2))System.out.print("B");}

Check the answer of this question online on QuizOver.com:Question: comparing null to StringPermalink: http://www.quizover.com/pdf/comparing-null-to-string


1.1.21. Question: What will be the Output?

What will be the Output?

Please choose only one answer: The code does not compile.Inner classOuter classThe code compiles but throws runtime exceptionOuter classInner class

Author: Sudhakar Nagarajan

public class InnerClassThis {int x=10;public void foo() { System.out.println("Outer class");}public class ReallyInner { public void foo() { System.out.println("Inner class"); } public void test() { this.foo(); InnerClassThis.this.foo(); }}public static void main(String... args) { InnerClassThis.ReallyInner i = new InnerClassThis().new ReallyInner(); i.test();}}

Check the answer of this question online on QuizOver.com:Question: Sudhakar Nagarajan What will be the Output?public class InnerClassThis {int x=10;public voidPermalink: http://www.quizover.com/pdf/sudhakar-nagarajan-what-will-be-the-output-public-class-innerclassthis-int-x-10-public-void


2. Chapter: Constructors

1. Constructors Questions




Please choose only one answer: Plant createdTree createdTree createdPlant createdRuntimeExceptionCompilation error


class Plant {Plant() {System.out.println("Plant created");}}class Tree extends Plant {Tree() {System.out.println("Tree created"); super();}}public class Test {public static void main(String args[]) {Tree tree = new Tree();}}

Check the answer of this question online on QuizOver.com:Question: When can call super() in java constructors?Permalink: http://www.quizover.com/pdf/when-can-call-super-in-java-constructors


2.1.2. Question: The following code contains one compilation error, where could it be?

The following code contains one compilation error, where could it be?

Please choose only one answer: At line 1, constructor Tester must be marked public like its classAt line 2, constructor call "this()" can only be called inside constructorsAt line 3, compilation error, ambiguity problem, compiler can"t determine wether a constructorTester or method Tester is called


public class Tester {Tester() { } // line 1 static void Tester() { this(); } // line 2public static void main(String[] args) { // line 3 Tester(); // line 4 }}

Check the answer of this question online on QuizOver.com:Question: How to call this() in java constructor?Permalink: http://www.quizover.com/pdf/how-to-call-this-in-java-constructor




Please choose only one answer: Won't compile because of line (1) constructor can't be private105050Won't compile because of line (5) constructor can't be static


public class Profile { private Profile(int w) { // line 1System.out.println(w);}public static Profile() { // line 5System.out.println(10);}public static void main(String args[]) {Profile obj = new Profile(50);}}

Check the answer of this question online on QuizOver.com:Question: Can java constructors be marked static?Permalink: http://www.quizover.com/pdf/can-java-constructors-be-marked-static


2.1.4. Question: Can a constructor be declared static?

Can a constructor be declared static?

Please choose only one answer: YesNo


Check the answer of this question online on QuizOver.com:Question: Can java constructors be declared static?Permalink: http://www.quizover.com/pdf/can-java-constructors-be-declared-static




Please choose only one answer: Won't compile because of line (1) constructor can't be privateWon't compile because of line (5) constructor can't be final501050


public class Profile {private Profile(int w) { // line 1System.out.println(w);}public final Profile() { // line 5System.out.println(10);}public static void main(String args[]) {Profile obj = new Profile(50); }}

Check the answer of this question online on QuizOver.com:Question: Can java constructors be declared final?Permalink: http://www.quizover.com/pdf/can-java-constructors-be-declared-final




Please choose only one answer: "AirPlaneIOException is thrown in AirJet" will be printed"AirPlaneIOException is thrown in AirJetIOException is thrown in Tester" will be printed"AirPlaneIOException is thrown in Tester" will be printedCompile error


import java.io.IOException;class AirPlane {public AirPlane() throws IOException {System.out.print("AirPlane");throw new IOException();}}class AirJet extends AirPlane {public AirJet() throws IOException { try {super(); } catch (IOException e) {System.out.print("IOException is thrown in AirJet");}}}public class Tester {public static void main(String args[]) {try { new AirJet();} catch (IOException e) {System.out.print("IOException is thrown in Tester");}}}

Check the answer of this question online on QuizOver.com:Question: How to call super() in java constructor?Permalink: http://www.quizover.com/pdf/how-to-call-super-in-java-constructor


2.1.7. Question: What are the legal modifiers which the constructor can be declared with?

What are the legal modifiers which the constructor can be declared with?

Please choose all the answers that apply: publicprotectedprivatefinalstaticabstract


Check the answer of this question online on QuizOver.com:Question: What are java constructors legal modifiers?Permalink: http://www.quizover.com/pdf/what-are-java-constructors-legal-modifiers


3. Chapter: Inner class

1. Inner class Questions


3.1.1. Question: What will be the result of above code ?

What will be the result of above code ?

Please choose only one answer: (1) Prints 9(2) Error during compilation at line 3(3) Error during compilation at line 5(4) Error during compilation at line 7

Author: Kausik LAST NAME

public class Test { public static void main(String[] args) { new OuterClass();// line 3 }}class OuterClass { private int x = 9; // line 5

public OuterClass() { InnerClass inner = new InnerClass(); // line 7 inner.innerMethod(); } class InnerClass { public void innerMethod() { System.out.println(x); } }}

Check the answer of this question online on QuizOver.com:Question: java inner class accessPermalink: http://www.quizover.com/pdf/java-inner-class-access


3.1.2. Question: What is the right output?

What is the right output?

Please choose only one answer: 6,65,67,67,7Complilation error in line 6Compilation error in line 5 inner class can't acces to private variables


class Outer { private int i = 5; // line 1

Outer(int i ){ // line 2 this.i = i; // line 3 System.out.print(++i); // line 4} class Inner{ Inner(){ System.out.print(","+ i++); // line 5 }}public static void main(String[] args) { int i = 6; Outer.Inner in = new Outer(i).new Inner(); // line 6 }}

Check the answer of this question online on QuizOver.com:Question: java inner class acces controlPermalink: http://www.quizover.com/pdf/java-inner-class-acces-control


3.1.3. Question: Are the lines 1 and 2 correct and free of compilation errors?

Are the lines 1 and 2 correct and free of compilation errors?

Please choose only one answer: Both statements at lines 1 and 2 are correctBoth statements at lines 1 and 2 are incorrect and cause compilation errorsCompilation error at line 1 , inner class can't access outer class local variablesCompilation error at line 2, inner class can't access method's arguments


public class AirPlane { public void fly(int speed) { final int e = 1;class FlyingEquation { {System.out.println(e);// line 1System.out.println(speed);// line 2 }} }}

Check the answer of this question online on QuizOver.com:Question: How to declare java inner class inside a method?Permalink: http://www.quizover.com/pdf/how-to-declare-java-inner-class-inside-a-method




Please choose only one answer: Compile error because of line 1 (incorrect instantiation)Compile error because of line 20 (can't access Airplane's variables)222211112211


public class OuterTest { public static void main(String args[]) { Airplane.BlackBox box = new Airplane().new BlackBox(); // line 1 box.printVariables();}}class Airplane {String code = "11";

class BlackBox {String code = "22";

public void printVariables() { System.out.print(code); System.out.print(Airplane.this.code); // line 20}}}

Check the answer of this question online on QuizOver.com:Question: How to access a member of an outer class from inside its inner class?Permalink: http://www.quizover.com/pdf/how-to-access-a-member-of-an-outer-class-from-inside-its-inner-class


3.1.5. Question: What statement,inserted independently at // insert statement here, would produceoutput "Body" ?

What statement,inserted independently at // insert statement here, would produce output "Body" ?

Please choose only one answer: return Body.name;return Body.this.name;return super.name;return this.super.name;


public class Body {String name = "Body";

public static void main(String[] args) {System.out.println(new Body().new Heart().getPName());}class Heart {String name = "Heart";

String getPName() {// insert statement here}}}

Check the answer of this question online on QuizOver.com:Question: How java inner class access outer class?Permalink: http://www.quizover.com/pdf/how-java-inner-class-access-outer-class




Please choose only one answer: Compile error because of lines 5-6 (incorrect instantiation)Compile error because of line 20 (can't access Airplane's variables)222211112211


public class OuterTest {public static void main(String args[]) {Airplane airplane = new Airplane(); //line 5Airplane.BlackBox box = airplane.new BlackBox(); // line 6box.printVariables();}} class Airplane {String code = "11";

class BlackBox {String code = "22";

public void printVariables() {System.out.print(code); // line 19 System.out.print(Airplane.this.code); // line 20}}}

Check the answer of this question online on QuizOver.com:Question: How to access an outer class member from inside its inner class?Permalink: http://www.quizover.com/pdf/how-to-access-an-outer-class-member-from-inside-its-inner-class


3.1.7. Question: Which of the instantiations for a BlackBox are correct and compile-free?

Which of the instantiations for a BlackBox are correct and compile-free?

Please choose all the answers that apply: Instantiation 1Instantiation 2Instantiation 3


public class OuterTest {public static void main(String args[]) {// instantiation 1Airplane airplane = new Airplane();Airplane.BlackBox box1 = airplane.new BlackBox();// instantiation 2Airplane.BlackBox box2 = new Airplane().new BlackBox();// instantiation 3Airplane airplane3 = new Airplane();BlackBox box3 = airplane3.new BlackBox();}}class Airplane {class BlackBox {}}

Check the answer of this question online on QuizOver.com:Question: How to instantiate an inner class inside main()?Permalink: http://www.quizover.com/pdf/how-to-instantiate-an-inner-class-inside-main


3.1.8. Question: whether program will compile?

whether program will compile?

Please choose only one answer: No, because local class can not be explicitly declared static.Yes its correct

Author: Aroraila975 LAST NAME

public class outer{public static void main(String[] a){static class inner{}}}

Check the answer of this question online on QuizOver.com:Question: java inner classPermalink: http://www.quizover.com/pdf/java-inner-class


3.1.9. Question: Which of the instantiations for a Engine are correct and compile-free?

Which of the instantiations for a Engine are correct and compile-free?

Please choose all the answers that apply: Instantiation 1Instantiation 2Instantiation 3Instantiation 4


public class AirJet {public static void main(String[] args) {// instantiation 1Engine engine1 = new AirJet().new Engine();// instantiation 2AirJet.Engine engine2 = new AirJet().new Engine();// instantiation 3AirJet airjet = new AirJet();Engine engine3 = airjet.new Engine();// instantiation 4Engine engine4 = new Engine();}class Engine{}}

Check the answer of this question online on QuizOver.com:Question: How to instantiate an inner class?Permalink: http://www.quizover.com/pdf/how-to-instantiate-an-inner-class


4. Chapter: Flow Control

1. Flow Control Questions




Please choose only one answer: 2No output is producedCompile ErrorRuntime exception is thrown24


public class LoopTest {public static void goLoop(int a) {start: for (int i = 1; i < 2; i++) {for (int j = 1; j < 2; j++) {if (a > 5) {break start;}System.out.print(i + j);}}}public static void main(String args[]) {LoopTest.goLoop(15);}}

Check the answer of this question online on QuizOver.com:Question: How to use break and continue in java for loop?Permalink: http://www.quizover.com/pdf/how-to-use-break-and-continue-in-java-for-loop


4.1.2. Question: What is the output of this code?

What is the output of this code?

Please choose only one answer: a) 2 Greenb) 2 3 Greenc) 2 3d) Compilation error at #1e) Compilation error at #2f) Runtime exception at #2

Author: Abhishek Sawant

public class SwitchTest{enum Color {RED,GREEN,BLUE};public static void main(String []args){Color clr = Color.GREEN;long x = 2;

switch(x){// #1case 1:System.out.println("1");break;

case 2:System.out.println("2");

case 3:System.out.println("3");break;

default:System.out.println("default");break;}switch(clr){ // #2case RED:System.out.println("Red");break;

case GREEN:System.out.println("Green");break;

case BLUE:System.out.println("Blue");break;}}}


Check the answer of this question online on QuizOver.com:Question: java switch control examplePermalink: http://www.quizover.com/pdf/java-switch-control-example


4.1.3. Question: what will be the output of compiling and running this code:

what will be the output of compiling and running this code:

Please choose only one answer: compiler errorprints 2Runtime exception is generated.prints 3

Author: Pankaj Gupta

class TestByte{public static void main(String arg[]){final Integer a=10;int b=2;switch(b){case 1: System.out.println("1");break;case 2: System.out.println("2");break;case a: System.out.println("3");break;}}}

Check the answer of this question online on QuizOver.com:Question: java switch statement rulesPermalink: http://www.quizover.com/pdf/java-switch-statement-rules


4.1.4. Question: Given the following code, which of if-statements declared is correctly written and causesno compilation error?

Given the following code, which of if-statements declared is correctly written and causes no compilation error?

Please choose all the answers that apply: stmt 1stmt 2stmt 3stmt 4stmt 5


public class Tester {public static void main(String[] args) {int x = 9;

// stmt 1if (x>0){}

// stmt 2if (x=9){} else {}

// stmt 3if (true){} else if (x


Check the answer of this question online on QuizOver.com:Question: Ho to write If-statement in java?Permalink: http://www.quizover.com/pdf/ho-to-write-ifstatement-in-java




Please choose only one answer: inside dooutsideoutsidecompilation error because of the second loop (while statement)


public class Tester {public static void main(String[] args) {do {System.out.print("inside do");} while (false);while (false) {System.out.print("inside while");}System.out.print("outside");}}

Check the answer of this question online on QuizOver.com:Question: do while loop syntax in javaPermalink: http://www.quizover.com/pdf/do-while-loop-syntax-in-java






public class LoopTest {public static void goLoop(int a) {outside: for (int i = 0; i < 3; i++) {inside: for (int j = 1; j < 3; j++) {System.out.print(j);if (a > 5) {continue outside;}}}}public static void main(String args[]) {LoopTest.goLoop(15);}}

Check the answer of this question online on QuizOver.com:Question: How to use break and continue in java labeled for loop?Permalink: http://www.quizover.com/pdf/how-to-use-break-and-continue-in-java-labeled-for-loop




Please choose only one answer: 0123Compilation error


public static void main(String[] args) {boolean flag = false;int x = 0;do {x++;} while (flag=!flag);System.out.println(x);}

Check the answer of this question online on QuizOver.com:Question: How to write do while statement in java?Permalink: http://www.quizover.com/pdf/how-to-write-do-while-statement-in-java




Please choose only one answer: Compile error, can"t use constant 1 in the switch, must be final variableCompile error, default must be the last statement after all the casesCompile error, must have break statement within each case1713


public static void main(String[] args) {int j = 10;switch (1) {case 20:j += 1;case 40:j += 2;default:j += 3;case 0:j += 4;}System.out.print(j);}

Check the answer of this question online on QuizOver.com:Question: How to write java switch statement?Permalink: http://www.quizover.com/pdf/how-to-write-java-switch-statement






public class LoopTest {public static void goLoop(int a) {start: for (int i = 1; i < 2; i++) {for (int j = 1; j < 2; j++) { if (a < 5) { break;} System.out.print(i + j);}if (a > 5) {break start;}}}public static void main(String args[]) {LoopTest.goLoop(15);}}

Check the answer of this question online on QuizOver.com:Question: How to write java labeled for loop?Permalink: http://www.quizover.com/pdf/how-to-write-java-labeled-for-loop




Please choose only one answer: Compile errorRuntime exception is thrown1123


public class LoopTest {public static void main(String args[]) {int a = 5;outside: for (int i = 1; i < 3; i++) {inside: for (int j = 1; j < 3; j++) {System.out.print(j);if (a++ > 6)continue inside; break outside;}}}}

Check the answer of this question online on QuizOver.com:Question: How to use continue and break in java loop?Permalink: http://www.quizover.com/pdf/how-to-use-continue-and-break-in-java-loop






public class LoopTest {public static void goLoop(int a) {start; for (int i = 1; i < 2; i++) {for (int j = 1; j < 2; j++) {if (a > 5) {break start;}System.out.print(i + j);}}}public static void main(String args[]) {LoopTest.goLoop(15);}}

Check the answer of this question online on QuizOver.com:Question: How to use break and continue loop control commands in java?Permalink: http://www.quizover.com/pdf/how-to-use-break-and-continue-loop-control-commands-in-java


4.1.12. Question: What is the result of running the following program (which was compiled fine) given thecommand line:

java Tester one two

What is the result of running the following program (which was compiled fine) given the command line:

java Tester one two

Please choose only one answer: one--two--onetwoonetwo--Tester--one--two--Testeronetwo--


public class Tester {public static void main(String[] args) {if (args.length > 0)for (String str : args)System.out.print(str);System.out.print("--");}}

Check the answer of this question online on QuizOver.com:Question: How to use java main method argument?Permalink: http://www.quizover.com/pdf/how-to-use-java-main-method-argument


4.1.13. Question: Which of the following is correct after running this code ?

Which of the following is correct after running this code ?

Please choose all the answers that apply: match will be printed 0 timematch will be printed one timedefault will be printed 10 timesdefault will be printed 11 times


public class Tester {public static void main(String[] args) {char code = 'a';for (int i = 1; i


4.1.14. Question: what is the result of running and the compiling the following code?

what is the result of running and the compiling the following code?

Please choose only one answer: Compile Time ErrorExceptionIntializerError is thrownInit BlockConstructor Runsstatic init 2Inside main method

Author: Nikhil Kumar

class ExamDemo3{static{new ExamDemo3();}{System.out.println("Init Block");}ExamDemo3(){System.out.println("Constructor Runs");}static{System.out.println("static init 2");}public static void main(String... args){System.out.println("Inside main method");}}

Check the answer of this question online on QuizOver.com:Question: static block order changed Nikhil KumarPermalink: http://www.quizover.com/pdf/static-block-order-changed-nikhil-kumar


4.1.15. Question: Knowing that character 'a' has a numeric value equal to 97, what is the output of thefollowing code

Knowing that character 'a' has a numeric value equal to 97, what is the output of the following code

Please choose only one answer: a

(int)aa (int)acompilation fails

Author: Pedro Kowalski

public class CaseTest {public static void main(String... s) {char c = 'a';

switch (c) {case 'a': {System.out.println("a");break;}case 97: {System.out.println("(int)a");break;}}}}

Check the answer of this question online on QuizOver.com:Question: switch with char variable in java pedro kowalskiPermalink: http://www.quizover.com/pdf/switch-with-char-variable-in-java-pedro-kowalski




Please choose only one answer: Compile Error at line 5Runtime exception is thrown at line 5Compile Error at line 8Runtime exception is thrown at line 8No output is producedCompile Error at line 4Compile Error at line 9Runtime exception is thrown at line 9


public class LoopTest {public static void main(String args[]) {int a = 15;outside: for (int i = 0; i < 3; i++) {// line 4inside: System.out.print(i); // line 5for (int j = 1; j < 3; j++) {if (a > 5) continue inside;//line 8break outside; // line 9}}}}

Check the answer of this question online on QuizOver.com:Question: How to use break and continue in java loop?Permalink: http://www.quizover.com/pdf/how-to-use-break-and-continue-in-java-loop


5. Chapter: Declarations and Access Control

1. Declarations and Access Control Questions


5.1.1. Question: Which of the following is true?

Which of the following is true?

Please choose all the answers that apply: When a class marked final, it cannot be extendedWhen a method marked final, it cannot be overriddenWhen a method marked final, it cannot be overloadedLocal variables of a method cannot be finalA variable of a primitive type (int,float,..) which marked final, its value at initializationcannot be changed


Check the answer of this question online on QuizOver.com:Question: what does final do in java?Permalink: http://www.quizover.com/pdf/what-does-final-do-in-java


5.1.2. Question: What is the output ?

What is the output ?

Please choose only one answer: Compilation errorIllegalArgumentException is thrown at runtime.Inside Demo10Hello 2Hello 2Inside Demo10

Author: Nikhil Kumar

class InitDemo{ static int i=demo(); static{System.out.println(i);} InitDemo(){ System.out.println("hello 1"); } public static void main(String... args){ System.out.println("Hello 2"); } static int demo(){ System.out.println("Inside Demo"); return 10; }}

Check the answer of this question online on QuizOver.com:Question: declarations and access control Nikhil KumarPermalink: http://www.quizover.com/pdf/declarations-and-access-control-nikhil-kumar


5.1.3. Question: (SCJP 6) Find the errors in:

(SCJP 6) Find the errors in:

Please choose all the answers that apply: line 1 - inside a method there can be only "final" and "default" variables, so line 1 should be removedline 1 - it would anyway not be allowed to define another "int a;" inside the constructor X()line 2 - "a" is not static inside X so it can not be called directly in a static context/main(), nor can it becalled directly on class XThe print lines inside main() will produce a compile-time error due to the quotes added to integervariablesStatic variables must be given a default value at their declaration time

Author: AlinaIoana Florea

class X{ X() { System.out.print(a); static int a; // line 1 a=4;

System.out.print(a); System.out.print(b); } int a; static int b;}public class Test extends X{ public static void main(String[] args) { X x = new X(); System.out.println(a + "" + x.a + X.a); // line 2 System.out.println(b + "" + x.b + X.b); }}

Check the answer of this question online on QuizOver.com:Question: java static vs non-static variablesPermalink: http://www.quizover.com/pdf/java-static-vs-nonstatic-variables


5.1.4. Question: What can be marked with strictfp modifier?

What can be marked with strictfp modifier?

Please choose all the answers that apply: an interfacea classa member methoda member fielda local variable


Check the answer of this question online on QuizOver.com:Question: strictfp modifier in javaPermalink: http://www.quizover.com/pdf/strictfp-modifier-in-java


5.1.5. Question: (SCJP6) Correct the following code:

(SCJP6) Correct the following code:

Please choose all the answers that apply: Final variables must be assigned an initial value, so the final variable "B" from line 1 must receive aninitial value at its declaration timeLines 2 and 4 must be removed as final variables can not be reassignedLine 5 must be removed as is not allowed to modify the object referred by a final reference variable


class X{ X() { System.out.print(B); final int B; // line 1 B=7; System.out.print(B); B=8; // line 2 System.out.print(B); } int a; final int B = 9; // line 3}public class Test{ public static void main(String[] args) { final X x = new X(); System.out.print(x.a); x = new X(); // line 4 x.a = 3; // line 5 System.out.println(x.a); }}

Check the answer of this question online on QuizOver.com:Question: java final variablesPermalink: http://www.quizover.com/pdf/java-final-variables


5.1.6. Question: You have three packages, trunk1,trunk2 and trunk3, What is the expected output ofcompiling and running file Tester?

You have three packages, trunk1,trunk2 and trunk3, What is the expected output of compiling and running fileTester?

Please choose all the answers that apply: AccountCurrentAccountAccountAccountCurrentAccount


package trunk1;

public class Account {Account() { //line 1System.out.println("Account");}}

package trunk2;

import trunk1.Account;

public class CurrentAccount extends Account{public CurrentAccount() { // line 2System.out.println("CurrentAccount");}}

package trunk3;

import trunk1.Account;import trunk2.CurrentAccount; // line 3

public class Tester {public static void main(String[] args) {Account c = new Account(); // line 4CurrentAccount ca = new CurrentAccount();}}


Compilation error in package trunk1 at line 1Compilation error, in package trunk2 at line 2Compilation error, in package trunk3 at line 3Compilation error, in package trunk3 at line 4

Check the answer of this question online on QuizOver.com:Question: packages and access scope in javaPermalink: http://www.quizover.com/pdf/packages-and-access-scope-in-java


5.1.7. Question: A top level Java class can have the following modifiers:

A top level Java class can have the following modifiers:

Please choose all the answers that apply: strictfp and finalabstract and finalpublic and abstractprotectedprivate


Check the answer of this question online on QuizOver.com:Question: class modifiers in javaPermalink: http://www.quizover.com/pdf/class-modifiers-in-java


5.1.8. Question: (SCJP 6) Find the errors in:

(SCJP 6) Find the errors in:

Please choose all the answers that apply: lines 1 - "static" can not mark classes and constructorsline 2 - "static" can not mark an initialization block {}lines 2 - "b" must be used instead of "a" as in a static context(method/init block) it's possible toaccess only static variableslines 3 - a non-static context can access only non-static variablesline 4 - a static method can access non-static variables("a"), but an error will occur because of theway "a" is commented leaving two "+" inside the print()line 6 - to be a valid override it must not be less accessible, so it must keep its static status + "static"is needed also because it's called directly in the static method main()


static class X // line 1{ static { a = 3; } // line 2 static X() {} // line 1 int a; static int b;

void doX(){ System.out.println("In X" + a + b); } // line 3 static void doStuff() { System.out.println("In X" + /*a*/ + b); } // line 4}public class Test extends X{ public static void main(String[] args) { X x = new X(); doStuff(); x.doStuff(); // line 5 X.doStuff(); // line 5.2 } void doStuff() // line 6 { System.out.println("In Test"); }}


Check the answer of this question online on QuizOver.com:Question: java static non inner classesPermalink: http://www.quizover.com/pdf/java-static-non-inner-classes


5.1.9. Question: You have two packages, trunk1 and trunk2 where class Sheet declared in trunk1and class Container declared in trunk2, the following code contains a compilation error, where could itbe?

You have two packages, trunk1 and trunk2 where class Sheet declared in trunk1and class Container declared in trunk2, the following code contains a compilation error, where could it be?

Please choose only one answer: In package trunk1 at line 2, constructor Sheet must be marked public like its classIn package trunk2 at line 1, invalid string argument for method main()In package trunk2 at line 2, invalid access to member pageNumberIn package trunk2 at line 3, invalid call to constructor Sheet()


package trunk1;

public class Sheet {public static int pageNumber = 99; // line 1Sheet() {} // line 2}

package trunk2;

import trunk1.Sheet;

public class Container {public static void main(String... args) { //line 1System.out.print(Sheet.pageNumber); //line 2Sheet sheet = new Sheet(); //line 3 }}

Check the answer of this question online on QuizOver.com:Question: How to access a class from another package in java?Permalink: http://www.quizover.com/pdf/how-to-access-a-class-from-another-package-in-java


5.1.10. Question: Consider the following two classes declared and defined in two different packages,what can be added in class B to form what considered a correct access to class A from main() method ofclass B?

Consider the following two classes declared and defined in two different packages, what can be added in class Bto form what considered a correct access to class A from main() method of class B?

Please choose all the answers that apply: at line 1 add nothingat line 2 add : new A();at line 1 add: import package.*;at line 2 add : new subPackage.A();at line 1 add: import subPackage.*;at line 2 add : new A();at line 1 add: import subPackage.A;at line 2 add : new A();at line 1 add nothingat line 2 add : new subPackage.A();


package subPackage;

public class A { }

package anotherPackage;// line 1public class B {public static void main(String[] args) {// line 2}}

Check the answer of this question online on QuizOver.com:Question: How to access java class from another package?Permalink: http://www.quizover.com/pdf/how-to-access-java-class-from-another-package


5.1.11. Question: What does it mean to mark a calss strictfp?

What does it mean to mark a calss strictfp?

Please choose only one answer: it means this class can't be subclassedit means this class can never be instantiated and it is to be extendedit means that any method code in the class will conform to the IEEE 754 standardrules for floating points


Check the answer of this question online on QuizOver.com:Question: strictfp in javaPermalink: http://www.quizover.com/pdf/strictfp-in-java




Please choose only one answer: Compile error at line 7 (static x must be only accessed inside static methods )Compile error at line 13 (static methods cant make reference to non-static variables )Compile error at line 16 (invalid argument type for method main )49Compile error at line 12 (must access x by writing Tester.x)


public class Tester {static int x = 4;int y = 9;

public Tester() {System.out.print(this.x); // line 7printVariables();}public static void printVariables() {System.out.print(x); // line 12System.out.print(y); // line 13}public static void main(String... args) { // line 16new Tester();}}

Check the answer of this question online on QuizOver.com:Question: What can java static methods make references to?Permalink: http://www.quizover.com/pdf/what-can-java-static-methods-make-references-to


5.1.13. Question: Given the following declarations, what is considered a correct statement?

Given the following declarations, what is considered a correct statement?

Please choose all the answers that apply: Eatable is ChewableVitamin is EatableFood is ChewableFood has VitaminVitamin has FoodFood is an Object


interface Chewable {}interface Eatable extends Chewable{}class Vitamin{}class Food implements Eatable { Vitamin[] vitamins;}

Check the answer of this question online on QuizOver.com:Question: types of relationships between java classesPermalink: http://www.quizover.com/pdf/types-of-relationships-between-java-classes


5.1.14. Question: (SCJP6) Correct the following code:

(SCJP6) Correct the following code:

Please choose all the answers that apply: line 1 - can not make a constructor final because it's not inheritable so it can not be anywayoverriddenlines 3 - can not extend/subclass a final classCan not use in class X2 the same variable and method names as in its superclass X1line 4 - can not override a final inherited methodline 5 - can not overload a final inherited methodline 2 - "final" can not be mixed with "private"


final class X1{ final X1() { System.out.print(B); } // line 1 final int B = 9;

final private void doStuff() {} // line 2}class X2 extends X1 // line 3{ final int B = 9;

final static void doStuff() { System.out.println("hello from X2"); }}public class Test extends X2{ public static void main(String[] args) { doStuff(); new Test().doStuff(3); } static void doStuff() {} // line 4 void doStuff(int arg) { System.out.println("hello from Test"); } // line 5}

Check the answer of this question online on QuizOver.com:Question: java final classes methods primitivePermalink: http://www.quizover.com/pdf/java-final-classes-methods-primitive




Please choose only one answer: Compile error at line 4 (static x must be only accessed inside static methods )Compile error at line 8 (constructors can't be static )Compile error at line 9 (static methods can't invoke this )Compile error at line 12 (invalid argument type for method main )44


public class Tester {static int x = 4;

public Tester() {System.out.print(this.x); // line 4Tester();}public static void Tester() { // line 8System.out.print(this.x); // line 9}public static void main(String... args) { // line 12new Tester();}}

Check the answer of this question online on QuizOver.com:Question: Can java static methods invoke this?Permalink: http://www.quizover.com/pdf/can-java-static-methods-invoke-this


5.1.16. Question: Spot the errors in:

Spot the errors in:

Please choose all the answers that apply: lines 1 - everything in Java must be within a classline 2- can not print hereline 3 - will produce a compilation error because it's using an invalid Java identifierthe "for" statement before line 3 will not compile because of the semicolon following itline 4 - an array must specify its size only when creating an object of its type not at declarationline 6 - will not compile because of the added quotesline 7 - will produce a run-time infinite loop which will crash JVM


static int x; // line 1static { System.out.println(x); x = 1; } // line 1class X{ int x; static int y; static Integer z = new Integer(1); System.out.println(x + y); // line 2 X() { for(int __x = 0; __x < 3; __x++) ; int #lb = 7; // line 3

long [] arr [5]; // line 4 Boolean []b[]; System.out.println(x + y + z); // line 5 System.out.println(x + y + "" + z); // line 6 System.out.println(new X()); // line 7 }}

Check the answer of this question online on QuizOver.com:Question: where declarations can go in java?Permalink: http://www.quizover.com/pdf/where-declarations-can-go-in-java


5.1.17. Question: Choose all the lines which if inserted independently instead of "//insert code here" willallow the following code to compile:

Choose all the lines which if inserted independently instead of "//insert code here" will allow the following code tocompile:

Please choose all the answers that apply: 1. void add(Integer... args){}2. static void add(int... args, int y){}3. static void add(int args...){}4. static void add(int[]... args){}5. static void add(int...args){} ;6. static void add(int... args1, int... args2){}


public class Test{ public static void main(String[] args) { add(); add(1); add(1, 2); } // insert code here}

Check the answer of this question online on QuizOver.com:Question: what is the correct usage of java var-args?Permalink: http://www.quizover.com/pdf/what-is-the-correct-usage-of-java-varargs


5.1.18. Question: Which of the following are NOT valid JavaBeans method identifiers for setters/gettersof private class variables?

Which of the following are NOT valid JavaBeans method identifiers for setters/getters of private class variables?

Please choose all the answers that apply: lines 1 and 9 - JavaBeans methods must be public in order to provide access to the private variablesof a classlines 2, 5 and 6 - according to JavaBeans "add" should be used only with listener methods, and "set"should be used instead of "put" and "modify"line 8 - will produce a compile-time error due to invalid Java identifierline 3 - the method's argument name should match the one its name: "customerName"lines 4, 7 and 11 - are adding or missing some thingsline 10 - it should be getHappy() because it's a getter method as it returns a valueline 12 - "nrOfFlowers" seems to be of type "int" not "boolean", as that's what the method isreturning, so it should be "get" instead of "is"


// Property setters:void setCustomername() // line 1public int modifyValue(int val) // line 2public void setCustomerName(String customer) // line 3public void setIsAlive(boolean isAlive) // line 4public void addSize(int size) // line 5public void putSize(int size) // line 6// Property getters:public int getMyValue() // line 7public int getAccount#(String clientName) // line 8protected boolean getHappy() // line 9public boolean isHappy() // line 10public boolean getHappy() // line 11public int isNrOfFlowers() // line 12

Check the answer of this question online on QuizOver.com:Question: legal javabeans method identifiers for setters /gettersPermalink: http://www.quizover.com/pdf/legal-javabeans-method-identifiers-for-setters-getters


5.1.19. Question: This is legal or not?

This is legal or not?

Please choose only one answer: legal and compile freeNo, there is compliation error(s)


final strictfp public class Parent implements Serializable {}

Check the answer of this question online on QuizOver.com:Question: java acces controlPermalink: http://www.quizover.com/pdf/java-acces-control


5.1.20. Question: Which of the following are NOT LEGAL Java identifiers according to the "javalanguage specification"?

Which of the following are NOT LEGAL Java identifiers according to the "java language specification"?

Please choose all the answers that apply: lines 1, 3, 4 - contain invalid characters for Java identifiersline 5 - is too longline 16 - in not a valid JavaBean identifier for a method that want to add a listener to an event sourcelines 6 and 8 - can NOT contain "#" and "." even if assigned to a numeric or floating point variableline 7 - can NOT contain the characters "-" and ":", nor can a Java identifier start with a digitlines 10, 11 and 14


int ; // line 1int ______9_y; // line 2int a; // line 3int b_, c; // line 4int this_is_a_way_too_long_name_for_an_identifier; // line 5int d3#; // line 6int -e, 7g, :h; // line 7float .f; // line 8double _$_$; // line 9int true = 10; // line 10int null = 4; // line 11int foo = 3; // line 12int Foo = 3; // line 13int continue = 6; // line 14int Volatile = 6; // line 15public abstract void addEvent(); // line 16

Check the answer of this question online on QuizOver.com:Question: legal java identifiersPermalink: http://www.quizover.com/pdf/legal-java-identifiers




Please choose only one answer: BaseDerivedDerivedException is thrown at runtimeCompilation error


class Base {private Base() {System.out.print("Base");}}public class Derived extends Base {public Derived() {System.out.print("Derived");}

public static void main(String[] args) {new Derived();}}

Check the answer of this question online on QuizOver.com:Question: Can java constructor be private?Permalink: http://www.quizover.com/pdf/can-java-constructor-be-private


5.1.22. Question: Correct the code in AnimalXyZ.java:

Correct the code in AnimalXyZ.java:

Please choose all the answers that apply: remove the "x#" comments, they are placed in wrong placesmove the package and the import statements at the beginning of the filemake "Animal" and "Dog" abstract as they do NOT implement the run() from the Runnable interfaceremove the "public" from "Dog", as only one class can be public in a .java file- rename "Animal" to "AnimalXyZ" as the only public class in a .java file must match the name of thefile- OR make ALL classes in the file "default""import java.lang.Runnable;" is necessary at beginning of the file


public /*x1*/ class /*x2*/ Animal implements Runnable {}package test2;/*x3*/import java.io.Serializable;/*x4*/public class Dog extends Animal implements /*x5*/ Serializable{ void /*x6*/ doStuff(/*x7*/int arg1, int /*x8*/ arg2) {} // wrong comments}class X{}class Y{}

Check the answer of this question online on QuizOver.com:Question: java comments packages importsPermalink: http://www.quizover.com/pdf/java-comments-packages-imports




Please choose only one answer: 099Compilation error at line 1, p must be initialized by a valueCompilation error at line 4, using uninitialized variable pCompilation error at line 11, p must be called using its class by writing Tester.p


public class Tester {static int p = test(); //line 1static public int test() {System.out.print(p); //line 4return 99;}public static void main(String[] args) { System.out.print(p);//line 11 }}

Check the answer of this question online on QuizOver.com:Question: How to use java static members?Permalink: http://www.quizover.com/pdf/how-to-use-java-static-members


5.1.24. Question: An inner class in java can have the following modifiers (at the same time):

An inner class in java can have the following modifiers (at the same time):

Please choose all the answers that apply: public and abstractabstract and finalprotectedprivate


Check the answer of this question online on QuizOver.com:Question: inner class modifiers in javaPermalink: http://www.quizover.com/pdf/inner-class-modifiers-in-java


5.1.25. Question: Correct the following code: (consider the packages as each being in a different file)

Correct the following code: (consider the packages as each being in a different file)



package pkgA;

public class X1{ X1() // line 1 { public int x1 = 11; // line 2 protected int x2=22; // line 2 int x3 = 33; private int x4 = 44; // line 2

System.out.println(x1 + "" + x2 + x3 + x4); // line 3 } public int x1 = 1; static protected int x2 = 2; int x3 = 3; private int x4 = 4;}class X2 extends X1{ private int x4 = 4; // line 3.5

public X2() { System.out.println(x1 + x2 + x3 + x4); // line 4 X1 x1 = new X1(); System.out.println(x1.x1 + x1.x2 + x1.x3 + x1.x4); // line 4 }}protected class X3 {} // line 5private class X4 {} // line 5//_____________________________________________________package pkgB;import pkgA.*;

class Y extends X1{ Y() { System.out.println(x1 + x2 + x3 + x4); // line 6.1 X2 x2 = new X2(); // line 7 X1 x1 = new X1(); // line 8 System.out.println(x1.x1+ x1.x2 + x1.x3 + x1.x4); // line 6.2 }}public class Test extends Y{ public static void main(String[] args) { new Test().go(); } void go() { System.out.println(x1 + x2); // line 6.1 Y y = new Y(); System.out.println(y.x1+ y.x2 + y.x3 + y.x4); // line 6.2


Please choose all the answers that apply: line 1 - X1's constructor must be public for "new" to succeed on line 8. And a similar thing is on line7, which will work only if the class X2 is made public in its package.lines 2 - local/method variables can be only "final" or "default"line 3 - won't compile because of the quotes added to those integersline 3.5 - is not allowed to define a var with the same name as in the superclasslines 4 - can not print "x4" as it's private in class X1 so it can be used only inside X1lines 5 - when defined in a package, classes are allowed to be also static, private or protectedlines 6 - should follow the same rules as the lines 4: "default" and "private" variables must beremoved + the "protected" vars kept only when used through inheritance: on lines 6.1

}}

Check the answer of this question online on QuizOver.com:Question: java access modiers for non inner classesPermalink: http://www.quizover.com/pdf/java-access-modiers-for-non-inner-classes


5.1.26. Question: Which of the following are NOT valid JavaBeans identifiers for methods thatadd/remove listeners from an event source?

Which of the following are NOT valid JavaBeans identifiers for methods that add/remove listeners from an eventsource?

Please choose all the answers that apply: lines 1 and 3 - the names of the methods do not match the type of argument they receive +JavaBeans adder/remover methods should always end with "Listener"line 2 - JavaBeans methods must be public in order to provide access to the private variables of aclass + it's missing an argument of type XListenerline 4 - it's adding or missing somethingline 5 - the name of its argument should be more meaningfulline 6 - it misses the event to be removedline 7 - should be "remove" instead of "delete"


// Event subscribers:public void addXListener(MyListener m) // line 1void addXListener() // line 2public void addEvent(Event e) // line 3public void addEventListener(EventListener e) // line 4// Event removers:public void removeMyListener(MyListener m) // line 5public void removeMyListener() // line 6public void deleteActionListner(ActionListsner m) // line 7

Check the answer of this question online on QuizOver.com:Question: illegal javabeans identifiers for methods that add /remove listenersPermalink: http://www.quizover.com/pdf/illegal-javabeans-identifiers-for-methods-that-add-remove-listeners


6. Chapter: Interfaces and Abstract Classes

1. Interfaces and Abstract Classes Questions


6.1.1. Question: Considering the following declaration for interface Convertable, which of the followingcode segments will compile?

Considering the following declaration for interface Convertable, which of the following code segments willcompile?

Please choose all the answers that apply: class Digit implements Convertable { public char convertToChar() { return 0; } public int convertToInt() { return 0; }}abstract class Digit implements Convertable { int convertToInt() ; char convertToChar();}abstract class Digit implements Convertable {

public int convertToInt() {return 0;}}abstract class Digit implements Convertable { public int convertToInt() { return 0; } char convertToChar();}


public interface Convertable {int convertToInt();char convertToChar();}


class Digit implements Convertable { int convertToInt() { return 0; }

char convertToChar() {return 0;}}interface Roundable extends Convertable {int roundUp();}

Check the answer of this question online on QuizOver.com:Question: What are the rules to implement an interface?Permalink: http://www.quizover.com/pdf/what-are-the-rules-to-implement-an-interface


6.1.2. Question: Correct the following code:

Correct the following code:

Please choose all the answers that apply: line 1 - a class(abstract or concrete) can not be emptyline 2 - interfaces must be "implemented" by non-interface classes, and "extended" only by otherinterfacesline 3 - to be a valid implementation/override, dress() must stay at least the same as available, so itmust keep the "public" access with which was marked automatically in its interfaceline 4 - is not ok as Dog is abstract so might not contain fully implemented methods from which tocreate a whole object. Also Bulldog has to implement play() as the version inherited from Dog is anoverload not an override.line 5 - to be a valid override barck() may not throw any exception if the class it overrides doesn'tthrow an exception. Nor is it valid for Bulldog to extend again Pet as it inherits it already from Dog.


interface Pet{ int MAX_PET_NR = 10; void play();}interface Dressable{ void dress();}interface Animal {} // line 1abstract class Dog extends Animal, Dressable, Pet // line 2{ public void play(int min){} void dress(){} // line 3 void bark(){}}class Bulldog extends Dog implements Pet{ Dog dog; Dog dog1 = new Dog(); // line 4 Dog dog2 = new Bulldog(); void bark() throws RuntimeException // line 5 { MAX_PET_NR = 2; // line 6 }; // line 5}


Check the answer of this question online on QuizOver.com:Question: how to implement java interfaces?Permalink: http://www.quizover.com/pdf/how-to-implement-java-interfaces


6.1.3. Question: Three of the methods are incorrectly declared, which are they?

Three of the methods are incorrectly declared, which are they?

Please choose only one answer: test1 , test2 and test4test2 , test4 and test5test1 , test4 and test5


public abstract class Tester {public void test1();public final void test2() {};public static void test3() {};public abstract static void test4();public abstract final void test5();}

Check the answer of this question online on QuizOver.com:Question: How to declare java abstract method?Permalink: http://www.quizov

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